Various industries now convey heavy parts or components mounted on expensive pallets, which may cost in excess of $20,000, on conveyor systems through an assembly or manufacturing plant for various operations, such as assembly, welding, painting and the like. As will be understood by those skilled in this art, such conveyor systems must be rugged, reliable and capable of stopping movement of the parts at various locations for such operations. Further, such operations may take different lengths of time and therefore such conveyors must be capable of staggering the parts on the conveyor system and then convey the parts to various locations for such operations.
A typical conveyor system of this type may include spaced lift tables which lift the parts from the conveyor for timed conveyance as required by the operations. Thus, movement of the parts or components on the conveyor are stopped, restarted and conveyed in different directions depending upon the needs of the manufacturing or assembly process. The sudden stops, restarts and changes in direction result in wear or damage to the conveyor system, the pallets and sometimes the parts conveyed. Thus, there is a continuing need for improvements in conveyor systems and methods of conveying parts, particularly heavy parts, which reduces wear and damage.
In an automotive manufacturing or paint facility, for example, vehicle bodies are typically conveyed through the manufacturing, assembly or paint facility for various secondary operations, including, for example, assembly of components on the vehicle bodies, welding, painting and other secondary operations. Such vehicle bodies are typically mounted on expensive pallets which generally include critical datums for locating points on the conveyed parts for such secondary operations. A typical conveyor system in an automotive manufacturing or paint plant includes continuous steel chains and the pallets include a hardened steel base. Nevertheless, the chain conveyors wear and must be periodically replaced. Further, the conveyors have retractable stops which engage and suddenly stop the pallets, damaging the pallets including the steel base, requiring periodic replacement of the pallets and the base cannot be used as a datum because of such damage.
The method of conveying elements and conveyor systems of this invention reduces or substantially eliminates wear or damage to the conveyor system when conveying heavy parts or components and pallets when the parts or components are mounted on pallets.